Research Plan: Activation of the contact system leads to production of bradykinin, a potent vasodilator and mediator of vascular permeability and pain, and kallikrein, which causes neutrophil activation and chemotaxis. To address the criticism that her original proposal was "largely descriptive and lacking depth" and without a "coherent theory of cell biology or pathology", Dr. Uknis has redesigned the project to begin by focusing on the basic biology of the synovium and its relationship to the contact system. Specifically, she hypothesizes that the synovium, and synovial fibroblasts in particular, potentiate the activation of the contact system by serving as an activating surface. Studies have been designed to demonstrate the binding of high molecular weight kininogen (HK) to synovial fibroblasts in both the inactivated state and following activation with phorbol esters. In response to the criticism that she "did not project the possibility of obtaining certain results which might have significant impact on current search", her preliminary data clearly indicate that the kallikrein-kinin system is, indeed, activated in rheumatoid arthritis. Her data are encouraging and supportive of her hypothesis. By studying interactions of the synovial fibroblasts with the contact system and exploring ways to prevent those interactions, she may ultimately be in a position to design novel therapeutic approaches for treatment of inflammatory arthritis. Similarly, the animal studies in Lewis rats with various inhibitors of the contact system are designed with a similar future goal. In response to the concern that she had not "already received a broad training", her accomplishments during the past year indicate that she, indeed, is well on her way to a career as a successful physician-scientist. She has continued to devote 80% of her time to research. She has continued to acquire skills and abilities, e.g. procedures for purification of platelet thrombospondin and fibroblast culture and cell binding studies. Finally, her most recent work on consensus sequences for glycosaminoglycan recognition on platelet thrombospondin will be presented at the annual meeting of the American Society of Hematology. In summary, the applicant has addressed the previous criticisms very well. Her approach and methods are feasible and her hypothesis is interesting. The planned work is a logical extension of her preliminary studies and may provide important, clinically applicable information.